The present invention relates to a new and improved method of applying or depositing flux powder or the like to the bath level of liquid metal within a continuous casting mold during continuous casting operations.
During the continuous casting of metals, typically steel, it is known to apply to the surface of the molten bath, in other words the bath level, within the mold a flux powder. The flux powder serves a number of different functions, namely to absorb non-metallic contaminants, as a lubricant between the walls of the mold and the cast strand, to prevent the oxidation of the steel and to maintain small the radiation of heat. In most instances, prior to casting, the flux powder is prepared in small heaps or piles at the mold covering. During casting the casting personnel or worker displaces the flux powder with the aid of suitable tools and depending upon requirements into the hollow mold compartment, i.e. onto the bath level. Consequently, at least one worker must be continuously present at the neighborhood of the continuous casting mold in order to insure for the proper application of the flux powder when needed. Since the flux powder lies around in an exposed condition oftentimes there are formed disturbing dust clouds of such powder.
According to a further solution which has been proposed in this particular field of technology the flux powder is stored in a container. At the lower end of the container there is arranged a conveying worm which transfers the flux powder into a mixing container. From that location the flux powder is entrained by a gas stream and blown through the agency of a stationary tube onto the bath level. In orer to avoid excessive development of dust the tube is divided at its end and widened into a distributor. The applied quantity of flux powder is determined ahead of time or accommodated to the momentary requirements by the operator during casting with the aid of a manual valve or equivalent structure.
Both proposals have been found to produce a highly irregular distribution of the flux powder over the entire region or surface area of the bath level. The uniformity of the distribution of the flux powder is markedly dependent upon the reliability and dexterity of the operator responsible for the application of the flux powder. Further difficulties can arise if there is present an unsuitable composition of the flux powder. Faulty distribution of the flux powder over the level of the bath leads to repeated surface defects, such as, for instance, longitudinal- and transverse fissures or cracks or markedly pronounced oscillation marks.